Japanese astronaut to throw paper planes to earth

Countless paper planes have been launched across classrooms from the hands of mischievous schoolboys; now Japanese scientists are preparing to unleash a high-tech version from 250 miles (400 km) above the Earth.

After successfully testing them this week, aeronautical engineers from Tokyo University believe the planes, made from heat-resistant paper treated with silicon, will survive the fiery descent back to Earth when they are released by a Japanese astronaut on the international space station later this year.

The planes, designed by the Japan origami airplane association, survived temperatures of 250C (482F) and winds speeds of Mach 7 - seven times the speed of sound - during their 30-second flight inside the university's hypersonic wind tunnel.

"Paper planes are extremely light so they slow down when the air is thin and can gradually descend," Prof Shinji Suzuki, who heads the team, told Reuters.

The engineers believe the technology could one day be adapted for use in unmanned spacecraft but for now, their more modest aims are to set a new world record for the longest flight by a paper plane and encourage children to take an interest in science.

While the 100 or so planes stand only a slim chance of striking land when they begin their journey in November, they will carry messages written in several languages and a request to send them back to Japan - the conventional way - should anyone be lucky enough to find one.

"It's going to be the space version of a message in a bottle," Suzuki said. "It will be great if someone picks one up."